Daduhe Bridge Xingkang

Daduhe Bridge Xingkang
大渡河兴康特大桥
Luding, Sichuan, China
935 feet high / 285 meters high
3,609 foot span / 1,100 meter span
2018

Crossing a wide reservoir from a downstream dam just north of Luding city, the giant Daduhe suspension bridge is the largest structure on the G4218 Ya'an to Kangding Expressway. Like many of China's Westernmost highways, this extension from the G5 expressway came many years after the more populous cities had already been connected in northern and eastern Sichuan Province. The Kanding route was especially difficult to construct with an amazing 82% of the road on bridges or in tunnels.

Located at kilometer 99, the alignment chosen for the Daduhe Bridge resulted in an unusual design for the east end where the anchorages had to be placed high up inside the steep mountain slope. To avoid compromising the strength of the deep underground anchorage, the engineers split the east-west lanes apart into tunnels separated by more then 100 meters, keeping the alignment off to the sides of the cable anchorage. The deck of the Daduhe Bridge is approximately 235 meters above the full lake level or 285 meters to the original level of the Dadu River.

The main cable has a 9.5:1 span to rise ratio with a diameter of 77 centimeters composed of 187 strands. Each strand has 91 parallel 5.3mm steel wires. The truss has a depth of 8.2 meters which makes for a width-to-span ratio of 1:40.7 and a height-to-span ratio of 134:1. The deck is supported by towers 188 meters tall. The exposed gravity anchor on the Kangding side has dimensions of 85 x 60 x 56 meters.

The construction of the truss will follow an unusual pattern first implemented on the Aizhai Bridge in Hunan Province where each truss piece will be pulled and rolled along with wheel bogies that travel along horizontal wires hanging from the suspender cables. The wheel bogies travel back to the cliff side staging area to carry another truss section out and the process repeats until the truss is completed.

Luding was already one of the most famous cities in Western China for its legendary chain bridge of 100 meters that ranked among the longest suspension bridges in the world since its completion in 1701. Several historic battles have taken place at or near the chain bridge due to its strategic importance, most notably during the Long March in 1935.

The Daduhe Bridge at Luding is one of at least a dozen major suspension bridges that have opened in China since 2009 that have span lengths of approximately a kilometer or longer and deck heights of 200 to 500 meters.

Daduhe Xingkang Bridge Elevation

雅康高速大渡河大桥是这条高速公路上最引人注目的工程，位于泸定县城以北，跨越一个宽阔的水库。就像中国西部边疆其他高速公路一样，这条高速公路是G5京昆高速的支线，在人口稠密的四川盆地内高速公路网建好后才开始修建。雅康高速公路难度极大，桥梁隧道占比达到惊人的82%。

该桥位于99公里处，由于地形的关系，这座桥有一个世界独一无二的设计，东端隧道锚锚固在引桥桥头隧道顶的山崖上。为避免隧道锚穿入桥东端公路隧道，东端的隧道是分离式的，入洞后不久就分开，中间间隔百米以上。隧道锚正好插入往返的高速公路隧道之间。此桥桥面高于泸定水库满水位235米，相当于大渡河原始水位280米高。

该桥钢桁梁使用轨索滑移法吊装，这种方法首次应用于湖南矮寨大桥，参见：